摘要
对7050铝合金进行固溶处理,随后在应变速率为1.0×10-4～1.0×10-1 s-1,温度为420℃及460℃的条件下进行拉伸测试。采用光学显微镜、扫描电镜及背散射技术对变形后的试样进行了检测。结果显示,在应变速率为1.0×10-1 s-1且温度为460℃时,铝合金具有最大的超塑性,伸长率达273%;在此变形条件下,塑性变形过程基本处于稳定状态,应力保持不变。微观组织从粗大晶粒变为双峰结构,并继续转变为接近均匀的细晶粒;随着超塑性应变的增加,动态复原过程从动态再结晶与动态回复转向完全动态再结晶。
The superplastic deformation behavior and microstructure evolution of 7050 Al alloy were investigated by tensile test under the temperature of 420 ℃ and 460 ℃ and strain rate of 1.0 × 10-4～1.0 × 10-1 s-1.The optical microscopy,scanning electron microscopy and electron backscatter diffraction were used to analyze the deformed samples.The results show that the solid solution treated 7050 Al alloy can gain the maximum elongation of 273% at 460 ℃ with the strain rate of 1.0 × 10-2 s-1 under the deformation condition.A large part of plastic deformation completes at an invariable stress.The microstructure transforms from coarse grains into bimodal microstructure and then into nearly uniform fine microstructures.The dynamic restoration process is from dynamic recrystallization plus dynamic recovery into dynamic recrystallization with the increase of strain during superplastic deformation.
出处
《热加工工艺》
CSCD
北大核心
2012年第4期5-7,共3页
Hot Working Technology
基金
国家自然科学基金(51105373)
材料成形与模具技术国家重点实验室资助项目(200908)
关键词
7050铝合金
大晶粒
超塑性
动态复原
7050 Al alloy
coarse grain
superplasticity
dynamic restoration
